Over 300 protesters were arrested overnight and the army was deployed in several Tunisian cities as violent demonstrations over prices, taxes and unemployment have swept the country.

In Thala, near the Algerian border, troops were sent in after protesters burned down the national security building forcing police to retreat from the town, witnesses told Reuters.

Violent anti-government protests have raged in other towns in the country since Monday, among them the tourist resort of Sousse, against prices and tax rises imposed by government to cut a ballooning deficit and satisfy international lenders.

While Tunisia is widely seen as the only democratic success story among "Arab Spring" nations, it has also had nine governments since the overthrow of authoritarian leader Zine El-Abidine Ben Ali, none of which have been able to deal with growing economic problems.

"Three hundred and thirty people involved in acts of sabotage and robbery were arrested last night," interior ministry spokesman Khelifa Chibani said, bringing the number of detainees since the protests began to around 600.